The invention relates to an electrodynamic braking device for a universal motor and to a method for braking a universal motor.
Electrodynamic braking devices are known in a variety of configurations.
The German patent publication DE 38 25 835 A1 describes an electric braking device for a series-wound motor having a field winding and an armature and having a circuit arrangement including a phase-angle control, wherein during the braking mode the field winding is fed from the power grid and the armature is short-circuited.
The braking device is specified for a centrifuge, whereby the braking torque is to be held constant over the entire speed range. The braking torque is controlled by a control device dependent on the rotational speed, wherein a current is produced in the exciter winding of the electric motor, which is inversely proportional to the rotational speed of said electric motor. Furthermore, a braking resistor is connected in series with the armature during the braking mode.
The German patent publication DE 102 34 397 A1 describes a braked series-wound motor and a method for braking the series-wound motor, according to which said series-wound motor is operated as a conventional series-wound motor in the motor mode, wherein means for switching to the braking mode allow for a bypassing of the armature and a separate excitation of the field winding by means of the supply voltage; thus enabling the motor in the braking mode to be operated as a separately excited DC generator.
The German patent publication DE 199 32 742 C1 discloses a further braking device.